import java.util.Scanner;

public class Test01 {
    public static boolean isAppear(int[] hash, char c){
        if(hash[c - 'A'] == 0)
            return true;
        else
            return false;
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String str = sc.nextLine();
        int[] hash = new int[60];
        for(int i = 0; i < str.length(); i++){
            if(isAppear(hash, str.charAt(i))){
                hash[str.charAt(i) - 'A'] = 1;
                System.out.print(str.charAt(i));
            }
        }
    }
}
